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Central Locking and Alarm Question

Z

zcacogp

Active member
Chaps,

This is related to (but separate from) Chris's Central Locking question ...

I have factory-fitted central locking on my S2. It also has the factory-fitted alarm, which is linked to the central locking. (i.e. Unlocking the car deactivates the alarm.)

I have found that when unlocking the car, the alarm will often sound. The way to stop the alarm from sounding is to activate the central locking system again, effectively 're-unlocking' the doors. I usually unlock the doors using the remote central locking, which is wired from the aftermarket alarm (i.e. not the factory-fitted alarm) to the central locking system.

I know that the actuator in the driver's door has five wires, and one of these is to signal to the central locking system that the driver's door is unlocked.

That much I know. Everything that follows is guesswork ...

I am guessing that the alarm is connected to the wire from a door actuator that signals when it is unlocked. Unlocking the car sets the alarm off if the signal is not sent properly to the alarm that the car has been unlocked.

'Re-unlocking' the door silences the alarm, presumably because it correctly signals to the alarm that the door has been unlocked and hence turns it off.

Does anyone know how the fact that the car is unlocked is sent to the alarm? If it is from the actuator in one of the doors then it is possible that the actuator is not sending the signal correctly, which could mean an iffy connection in the actuator.

If it is NOT from one or other of the actuators, does anyone know how it is sent?

All help, suggestions or guidance welcome - thanks.


Oli.
 
As far as I have worked it out. It's the micro switch on the door lock that tells the alarm that the door is unlocked. My car will only start if you unlock the drivers door with the key.If you go in through the passenger side the car will crank but not start.
 
must be the weather i'm having the same prob and its going off a lot, can it be turned off on my 91?
 
Colin,

Thanks - that's VERY helpful. I've printed out the wiring diagrams and am studying them as I write this, but am concluding that there isn't enough information in them to answer my question (the wiring inside the central locking control unit isn't shown).

If what you say is the case, why does my car usually start? I usually unlock it with the remote central locking - i.e. there is no key in the driver's door lock.

Also, unlocking the car not using the driver's door lock would mean the car is still alarmed. So why doesn't it go off in your case?


Oli.
 

ORIGINAL: strath44

must be the weather i'm having the same prob and its going off a lot, can it be turned off on my 91?
Click to expand...
Wiring diagram says that if you remove the alarm control box and bridge the Green with Black/White wire, and the Black with the Yellow/Red wire then everything will work but the alarm is out of circuit.


Oli.
 
Chaps,

Update on this; Colin is spot on in that the alarm is driven from the driver's door lock. If the door lock is registered as 'open' then the alarm is turned off. By the description of my original problem, this should be enough to diagnose and solve my problem.

However I not have some more diagnostic information; on a couple of occasions over the weekend the car has unlocked without the alarm sounding, and the door opened, but the alarm has gone off when you put the key in the ignition and tried to start it. This suggests to me that there is something more complex than a simple poor connection somewhere, and that the alarm itself may be defective in some way.

On that basis, I'm going to remove the alarm entirely. The car has another alarm and two other immobilisers anyway, so there is no major dent in the security as a result!

So, has anyone removed one of the standard-fit alarms from their 944? I think they are Hayward and Scott devices, and may not have been fitted at the factory (they could have been dealer-fit.) If am guessing I short out the wires as mentioned in my post above (^^^) and remove the alarm control box. Is there also an alarm relay? The wiring diagram suggests there is, and I guess I remove this as well. Does anyone know where the 'alarm horn' is? The wiring diagram suggests it is a seperate unit to the normal horn, and hence should probably be removed as well.

All suggestions welcome, thanks.


Oli.
 
I'm no electrician so can't really help except to say the standard fit alarm was made by http://www.hamilton-palmer.co.uk/ (the other place you mentioned do the custom exhausts )

Hamilton Palmer had a good reputation for being very helpful in the supply of spare keyfobs for the immobiliser, so may be worth a call?
 
the sounder is in the scuttle area beside the fusebox - the actual horn(s) are in front of the nearside wheel.
 
Smiffy, Tony,

Thanks both of you.

Paul - I think I'm probably a bit happier just to remove the alarm altogether. Yes I am sure they would be helpful but the alarm isn't really necessary and removal means it will never go wrong again!

Tony - thanks. I can't recall having seen it but I'll go a-huntin'.

I think I'll do some other stuff while I am delving into the alarm electrics, including wiring up one of the function outputs on the aftermarket alarm to the windows so they can be closed automatically. I'm waiting for some electrical connectors to be delivered and will dive on in then.


Oli.
 
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